System for mining a soluble



July 30, 1935. E, N. TRUMP SYSTEM FOR MINING' A SOLUBLE Filed Aug. 12, 1953 S Sheets-Shet 1 July 30, 1935. E. N. TRUMP 2,009,534

SYSTEM FOR MINING A SOLUBLE Filed Ag. 12, 1935 5 Sheets-Sheet 2 1y Indenior Z'Mrdiffizmzp,

July 30, 1-935. E. N. TRUMP 7 2,009,534

I SYSTEM FOR MINING A SOLUBLE Filgd Aug. 12. 1935 s Sheets-Sheet 3 fli'ior' ej I Patented July so, 1935.

UNITED STATES PATENT OFFICE 2,009,534 sYs'rEMFon MINING A SOLUBLE Edward N. Trump, Syracuse, my. Application August 12, 1933, Serial No. 684,801

7 Claims. (Cl. zeHi My invention relates to improvements in means for mining a soluble. It has been common practice for many years to mine a soluble such as salt .by introducing a solvent, such'as water, by means of a hole drilled into the bed of rock salt and withdrawing the solution therefrom.

It has even been proposed to introduce anonsolvent, such as air, into the minecavity to protect the roof of the cavity from the solvent, and, as the cavity increases outwardly and downwardly, to introduce more air to protect the increasing dimensions of the cavity roof; this procedure being repeated from time to time until the cavity has spread out to such an extent-that the roof of the cavity caves in, after which the protective layer is no longer employed.

As all impurities fall to the bottom of the cavity, eflicient downward dissolving is not eilected, as the sediment, falling upon the bottom water upon the salt beneath.

In accordance with the present invention,

means are provided for controlling the protective layer of non-solvent, such as air,- either with 86 respect to volume or' pressure, in order to secure from time to time the required top level of the solvent, and this level of the solvent is changed, step bystep upwardly, so that the salt may be dissolved from beneath upwardly in stages.

undercut the bed, from the bottom up, for as small a height as posible, by maintaining a layer of non-solvent, such as air, which will float on the surface of the solvent to protect the roof of the cavity, until the desired diameter is secured. The required level of the solvent is maintained by introducing a surplus of air into. the cavity so that there will be a continuous discharge of' surplus air at a determined level, or, by controlling the pressures as hereinafter described. After the desired horizontal diameter ofthe cavity is secured, by changing the point of discharge, or the dlil'erential pressure of the air, the level of the solvent is permitted to rise, and thus the dissolving proceeds step by step upwardly as described.

The advantages of the means for securing such procedure are as tollows:-

As the salt bed is attacked gradually, step by step, upwardly from below, the cavity becomes bell-shaped, that is, formed with an arched roof, so that thebed may be almost. entirely dissolved before the roof breaks.

As the solution or brine naturally takes the of the cavity, interfereswiththe action of the By starting at the bottom of the salt bed, I-

lowest position in the mine cavity, the fresh water -is always in contact with the salt in the-upper part of the cavity. Hence dissolvingupwardly from below is eifected with maximum efficiency.

By providing means for causing a separation of V the solution discharging from the mine cavity, at 5 a point below the introduction of fresh solvent,

a' richer solution is secured.

By providing means for introducing air mixed with the water under pressure, the air is absorbed by the water as the pressure increases, and much 10 less pressure is required 'thanwhen the air and water are introduced separately.

By providing means for permitting the escape of surplus air with the brine, less-pressure of introduced water and air is required: when the wa- 15 ter is saturated with salt, three quarters of'the air is driven out of the solution. V v

Further advantages will appear in the following descriptio'n of my improved means.

This application is a continuation, in part, of 20 of my application Serial No. 574,149, filed Nov. 10, 1931, now-matured into Patent No. 1,923,896, dated August 22, 1933.

Referring tothe drawings, which illustrate, merely by 'way of example, suitable embodi- 25 ments of my invention;

Fig. 1 is a diagrammatic vertical section showing one form of embodiment.

Fig. 2 is a similar view of another form.

Fig. 3 is a similar view of another form.

Fig. 4 is a similar view of another form.

Fig. 5 is a similar view of another embodiment.

Fig. 6 is a similar view of another embodiment.

Fig. 7 is a fragmentary vertical section show- 36 ing a diiferent arrangement.

Fig. 8 is a diagrammatic view indicating the shape which the cavity will assume during the dissolving.

Similar numerals refer to similar parts through- 40 out the several views.

The well, as shown in Fig. 1, is cased with 10" tube I through gravel into rock. An 8" casing 8 is cemented into lower part of shale roof and upper part of salt bed. A 6" casing 9 extends to to the top of the undercut-and a 3" tube It to bottom of the salt. Such an arrangement is adapted to undercut a rock salt bed, as for example, in a 1500 it. well with 100 ft. of salt With the arrangement shown in Fig. l, the water, 'atpressure of about 200 pounds'to the square inch, is pumped into the 3" tube or casing I 0, passing into the cavity where it circulates and dissolves saltioff the circumference of the cavity and flows upwards through the anll nular space between the tubes 9 and M, as partially saturated brine.

To prevent attack of the salt above the end of the tube 9, "air, of about 700 pounds per square inch pressure, is pumped into the annular space between tubes 8 and 9, forcing the waterdown until the air bubbles under the end of tube 9. This will maintain the water level at this level and an air cushion will fill the space betweenthe ripples on top of the brine as long as there is a surplus of air kept movis piped with a 3" tube II to the bottom of the salt, and a 6" .tube I2 is packed off in the 8" tube [3 which is cemented in the rock. The 6" tube l2'may be stopped at the top of the salt or extended down into it to top of the undercut I as shown.

The well is operated by forcing water down the annular space between. tubes II and I2, and brine out of tube ll. Air is forced in with the 'waterand entrained in the form of bubbles,

which reduce in size by absorption and increase of pressure. The air is therefore compressed to the pressure of the water at the bottom of the well and holds back the liquid to required level.

Small holes l3 in tube II, at level of top of undercut, allow surplus air to escape into the brine, thereby regulating the level of air which fillsthe space around the tubes to the underside of packer. This arrangement reduces the pressure of air needed to the pressure of the water. at top of well instead of the bottom as in Fig. 1. 1

In accordance with the modification shown in Fig. 3, the 3 tube 14, reaching to the bottom of the salt, is provided with a bell l5 which is either part ofthe 6" tube It or will slide down through it. This bell receives the surplus air at the level of the top of the undercut and transfers it, through small holes or passages l1, into the 3" tube [4.

The water is forced down through the annular space between the tubes l4 and I6 and out through holes or space l8 above the bell l5.

Air is forced through the crown of small tubes 19 into the water and is carried down entrained as small bubbles subject to increasing pressure.

The amount of air absorbed increases with the depth and pressure of the water. As the salt dissolves, it drives out a portion of the air which has. been absorbed. If a surplus of air, over the amount absorbed, any leakage and the volume required to fill the space around the tube up to the packer, is forced in, the surplus escapes under the bell and, entering the tube l4, helps to elevate the brine passing up this tube.

- In accordance with the modification shown in Fig. 4, the 8" casing 20 is cemented into the rock and the top of the rock salt bed. a

A 6" casing 2| is extended down nearly to the level of the undercut. I

A 8- tube 22 extends to the bottom of the salt.

The connections of water and brine and-air pipe are arranged so that the well can be operated either way, with brine or water in the 3" tube 22.

A 1" pipe 23 is suspended inside the 3" tube 22,.

with its bottom end at the top of desired undercut. This 1" pipe 23 maybe very readily moved up or down or changed in position, to regulate the level of the air cushion, and consequently the top level of the solvent, outside of the 3" tube 22.

The air which is forced into the water through the crown of small tubes I9 is carried down with the water, and the surplus fills the space between the tubes 20 and 2| to the top of the well.

. This space between 20 and 2| is connected, through a piping 23, to the 1" center pipe 23, and the surplus air passes out of this space, to and through the 1" center pipe 23 into the 3" pipe 22.

If this pipe 23 and piping 23' arewide open, the level of the top of thewater outside the 3" tube 22 will be enough below the end of the 1" pipe 23 to overcomethe friction of the air passing up the annular space, through the piping and valves and down the 1" center pipe 23.

If a reducing valve 28, shown in the piping 23', is set to obstruct the air, the level of the air cushion will be lowered the amount of the differential pressure measured in feet of water.

With a 1500 ft. well with weak brine, 18 cu. ft. of air per-minute will maintain the level with very little surplus. When the brine is saturated,

only 6' cu. ft." are required.

With this amount of air the friction .in the tubing will be negligible and the level will be very little below the end of the 1" pipe 23, when the reducing valve is wide open.

The above amounts are when using 20 cu. ft.

of water=200 gal. per min.

In Fig. 4 are also shown air gages 25 and 26, the mercury gage 21 and a reducing valve 28, the hand pump 29 and also a number of valves in the air line, the water line and the brine line, whereby the several flows and the direction of flow may be controlled. Also the center air pipe 23 may be arranged for change of vertical position.

.By the proper manipulation of these several instrumentalities, the level of the solvent may be regulated during the several stages as required.

Thisarrangement of well eliminates all packers, uses simple tubing without any connection between them at the bottom, and the regulation is all accomplished at the top of the well. The level can be varied at will,

The air indicator 30, is suspended in the space between pipes 20 and 2|. The bottom end being below the top of theundercut. The hand air pump 29 is operated to force air into the tube ill until it bubbles under the bottom end. The difference in pressure indicated between gage 25 and gage 26, shows the distance between the. water level and the bottom of the air indicator-pipe 30.

In Fig. 5, is'shown a structure similar to that shown in Fig. 4, somewhat simplified. It also illustrates the form which the cavity assumes during dissolving. In addition to the parts, as numbered in Fig. 4, 32 indicates the inlet for fresh water, 33 the air inlet pipe, 34 the discharge pipe for brine.

In accordance with the-arrangement shown in Fig. 6 the annular bell 38 surrounds the brine tube 22, with its lower margin approximatethe top of the desired undercut. This bell is supported upon a number of air pipes 31 and may be raised from time to time as the dissolving proceeds upwardly in stages, without changing the center brine pipe 22. These air'pipes 31 are adapted to, deliver the air to central pipe 23. An injector 38 is shown in this figure, which is adapted to utilize the air under pressure delivered through pipes 31 from hell 36, in introducing air with the water at the top of tube 2|.

In accordance with the arrangement shownin Fig. 7, a bell 39 is provided to surround the brine tube 22. The bottom-of the bell is approximate the top of the undercut, and the air coming down with the water between casings 2| and 22 separates from the water and passes under said lower margin of the bell. A plurality of small tubes 40 are connected to the brine tube 22 as at! I. These tubes project upwardly in the bell and are open at the top so that, as the bell fills with air under pressure, the surplus air will enter the brine tube 22 through these tubes 40 without danger of carrying fresh water therewith. The position of the lower margin of the bell will define the level of the water in the mine cavity.

Fig. 8 indicates the approximate shape of the roof of the cavity 42 as the dissolving progresses upwardly. The arched formation of the root of this cavity makes it po sible to dissolve almost the entire bed of salt before the roof caves in.

By soluble is meant salt or other mineral capable of being dissolved.

By solvent is meant any fluid medium capable of dissolving the soluble.

By non-solvent is meant any fluid medium which will not dissolve the soluble.

What I claim is:-

1. In a system for mining a soluble by introducing a solvent into a cavity formed in the sol-' uble and discharging the resulting solution, means for controlling and changing as required the level of the solvent in the cavity, comprising a pipe for introducing the solvent, a pipe for discharging the solution, means for introducing compressed air into said cavity above the solvent, an adjustable air pipe discharging into the solution pipe at a point near the level of the solvent in said cavity, and means for delivering air from the cavity tosaid air pipe.

2. In a system for -mining a soluble by introducing a solvent into acavity formed in the soluble and discharging the resulting solution,- means for controlling and changing as required the level of the solvent in the cavity, comprising a pipe for introducing the solvent, a pipe for discharging the solution, means for introducing compressed air into said cavity above the solvent, an air pipe discharging into the solution pipe at a point near the levelof the solvent in said cavity, a pipingconnecting the air space in the cavity with said air pipe, said connecting piping provided with a reducing valve.

3. In a system for mining a soluble by introducing a solvent into a cavity formed in the soluble and discharging the resulting solution, means for controlling and changing as required the level of the solvent in the cavity, comprising a pipe for introducing the solvent, a pipe for discharging the solution, mesns for introducing compressed air into said cavity above the solvent, an adjustable air pipedlscharging into the solution pipe at a point near the level of the solvent in said cavity, a piping connecting the air space soluble and discharging the resulting solution,

means for controlling and changing as required the level of the solvent in the cavity, comprising a pipe for introducing the solvent, a pipe for discharging the solution, an annular bell surrounding the solution pipe having ,the margin of its open end approximately at the level of the solvent, an adjustable air pipe discharging into the solution pipe at a point near the level of the solvent in the cavity and means for delivering air from the bell to the air pipe.

5. In a system for mining a soluble by introducing a solvent into a cavity formed in the soluble and discharging the resulting solution, means for controlling and changing as required the level of the solvent in the cavity, comprising a pipe for introducing the solvent, a pipe for discharging the solution, an adjustable bell surrounding the solution pipe having the margin of its open end approximately atthe level of the solvent, and an air pipe discharging from the bell to the solution pipe. I

6. In the operation of dissolving a soluble by introducing a solvent-into a cavity made in the soluble, introducing also a non-solvent for controlling the action of the solvent, 'and discharging the solution fromsaid cavity, the method which consists in controlling the top level oi the solvent first to secure dissolving outwardly in a horizontal plane close .to the bottom of the cavity, in order to undercut the mass of soluble, and then to permit the dissolving in stagesupwardly until substantially the entire mass of soluble is dissolved.

v 7. In the operation of dissolving a soluble by introducing a solvent into a cavity formed in the soluble, introducing also a non-solvent for controlling the action or the solvent, and discharging the solutionfrom-the bottom of the cavity, 

